More than $640 million worth of Bitcoin ( BTC ) flowed out of crypto asset manager Grayscale’s spot Bitcoin ETF on March 18, marking the largest day of outflows for the fund since its conversion to a spot ETF on Jan. 11. 

Grayscale notched a total of $642.5 million in outflows on March 18., At the same time, inflows into Fidelity’s Bitcoin ETF — the second-largest fund — stumbled to just $5.9 million, its lowest day on record, according to data from Farside Investors.

Grayscale Bitcoin ETF shed the largest amount in a single day on record. Source: FarSide

At the time of publication, the price of Bitcoin is trading at $65,875, down 10.5% from its latest all-time high of $73,797 which it notched on March 14, per CoinGecko data . 

Several market commentators have pointed to slowing Bitcoin ETF flows, the upcoming halving event, and the United States Federal Reserves FOMC meeting on March 20 as justifications for BTC’s depressed price action over the last few days.

However, other analysts have shared an optimistic outlook for Bitcoin ETF flows moving forward.

Grant Englebart, the vice president of investment firm Carlson Group, told Bloomberg TV that only a “handful” of his firm’s advisers had seen clients allocate funds to Bitcoin ETFs, noting that of that allocation, there had been an average investment ratio of 3.5% of total funds.

Commenting on the interview, X Bloomberg ETF analyst Eric Balchunas said that the interview aligned with what he had been hearing from Bitcoin ETF fund issuers — that only a handful of early adopters had been picking up a meaningful allocation to spot Bitcoin ETFs.

Balchunas said only a handful of “early adopters” had picked up meaningful Bitcoin ETF allocation. Source: Eric Balchunas on X

“So far it’s only ones into BTC already, they are [a] ‘handful’ of early adopters inquiring, then making allocations,” Balchunas said.

“Advisors are not yet soliciting the rest of their clients. All these flows are from inbound traffic,” added Balchunas, hinting that Bitcoin ETF inflows could continue to gather steam in the future.

Other commentators pointed to the remaining amount of Bitcoin on GBTC’s books — roughly 370,000 Bitcoin — as justification for a long-term bullish outlook on ETF flows.

“GBTC had 378k Bitcoin and today sold 9.6k Bitcoin. Good news is that they cannot go on with this pace for so long,” wrote crypto market commentator Allesandro Ottavani in a March 19 post to X.

Grayscale Bitcoin Trust was converted from an institutional fund to a spot ETF on Jan. 11, alongside the approval of nine other spot Bitcoin ETFs from fund issuers including BlackRock and Fidelity.